Process for manufacturing carbon fiber fabrics and fabric manufactured with this process

ABSTRACT

Process for manufacturing carbon fiber fabrics, in which a fabric of carbon fiber ( 1 ) is impregnated with a silicone, polyurethane or acrylic emulsion ( 4 ) which is then dried together with the fabric ( 1 ). The present invention also relates to a fabric manufactured with this process as well as a coating for motor vehicles comprising this fabric.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a 371 of PCT/IB2013/051113, filed Feb. 11, 2013,which claims the benefit of Italian Patent Application No.MI2012A000245, filed Feb. 20, 2012, the contents of each of which areincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a process for manufacturing carbonfiber fabrics, in particular a flexible fabric that can be used to coatinner parts of motor vehicles. The present invention also relates to acoating for motor vehicles comprising this fabric.

BACKGROUND OF THE INVENTION

Known carbon fiber fabrics comprise a web of thin filaments of carbonfibers arranged perpendicularly to each other. These known fabrics areimpregnated with polymeric resins and overlapped according to suitabledirections. The resins are cured to obtain rigid materials with a highspecific resistance, which are suitable for the production of structuralparts or aesthetic parts. These materials, because of their stiffnesscharacteristic, cannot be applied for example to the internal parts ofmotor vehicles, where flexible fabrics that can be sewn and folded arerequired. This also excludes the use of raw fabrics made of carbonfiber, which tend to unthread and are not able to keep unchanged thearrangement of the fibers once deformed.

SUMMARY OF THE INVENTION

The object of the present invention is therefore to provide a fabricmade of carbon fiber free from said drawbacks. Said object is achievedwith a process, a fabric and a coating, whose main features arespecified in the claims.

Thanks to its particular features, the fabric according to the presentinvention can be advantageously used for products and accessories ofclothing or leather goods, in particular bags, as well as for otherapplications requiring a flexible fabric, such as for example coatingsof seating and interior walls, in particular of motor vehicles. In fact,the fabric according to the present invention does not fray even whenthe fibers are stressed by the seams. Furthermore, even if deformedalong two transversal axes of curvature, namely with concave or convexdeformations, the fabric maintains a substantially perpendiculararrangement and a limited longitudinal sliding of the fibers, so as toavoid permanent deformations of its structure.

A particular protective layer is preferably applied to the fabric toimprove the handling during the manufacture and/or to limit theflexibility of the fabric, as well as to make it resistant, waterproof,insulating, semi-transparent, non-transparent and/or opaque.

The fabric according to the present invention is pleasant to the touchand has a high resistance, superior to that of a raw fabric of carbonfiber, while retaining an extreme flexibility which allows also tocreate folds or hems on the same fabric without compromising theintegrity. The fabric is also very elastic since its particularimpregnation ensures a correct arrangement of the texture even afterdeformations. It is therefore possible to deform this fabric withoutcompromising its texture and without causing unthreadings between thefibers.

According to an aspect of the invention, the particular silicone,polyurethane or acrylic emulsion also impregnates the most inner fibersof the fabric of carbon fiber, so as to obtain a fabric resistant tosurface wear, but still extremely flexible.

At least one edge of the fabric in its final configuration is preferablyfolded and sewn on itself, so as to form a hem that prevents unthreadingof the fibers of the most inner layers of the fabric.

Further advantages and characteristics of the fabric and of the processaccording to the present invention will become apparent to those skilledin the art from the following detailed and non-limiting description ofan embodiment thereof with reference to the accompanying drawings inwhich:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a partial section of the fabric during a step of theprocess;

FIG. 2 shows the fabric of FIG. 1 during a subsequent step of theprocess;

FIG. 3 shows the fabric of FIG. 1 during a subsequent step of theprocess; and

FIG. 4 shows the fabric of FIG. 1 during a further step of the process.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, it is seen that fabric 1 according to the presentinvention comprises at least a weave, in particular cloth, twill orsatin weave, of yarns of carbon fiber having a linear density between 50and 5000 g/km and comprising from 1000 to 60000 filaments, in particularfrom 3000 to 24000 filaments having a diameter comprised between 5 and10 microns. The thickness of fabric 1 is comprised between 50 and 1000microns. The basis weight of fabric 1 is comprised between 170 and 270g/m², in particular 210 and 220 g/m².

In a first preliminary operating step, to ensure the regularity and agood aesthetic finish of the weave, fabric 1 is brushed and/or stretchedat a temperature comprised between 30° and 200° and/or at a pressurecomprised between 1 and 100 bar by means of two cylinders or two platessuitable to exert a variable pressure.

In a second preliminary operating step, at least one protective layer 2,in particular comprising a film, a woven fabric or a nonwoven fabric,more particularly a polyurethane, polyamide or acrylic film, is appliedonto one side of fabric 1. The thickness of the protective layer 2 iscomprised between 50 and 500 microns. The basis weight of the protectivelayer 2 is comprised between 20 and 40 g/m², in particular 25 and 35g/m². The protective layer 2 is applied to fabric 1 by means of alamination, in particular a hot calendering or pressing, in which fabric1 and the protective layer 2 are laminated together at a temperaturecomprised between 30° and 200° and/or at a pressure comprised between 10and 200 bar. During this operating step the surface of the protectivelayer 2 in contact with fabric 1 partially penetrates fabric 1, so as tocreate an intermediate layer 3, having a thickness comprised between 5%and 60% of the thickness of fabric 1, in which the outer filaments offabric 1 are integral with the protective layer 2.

Referring to FIG. 2, it is seen that in a main operating step fabric 1is impregnated with a silicone, polyurethane or acrylic emulsion 4 bymeans of sprayers 5, or by smearing, immersion or with a “hot-melt”transfer procedure. Sprayers 5 are arranged on the opposite side offabric 1 with respect to the protective layer 2, namely fabric 1 iscomprised between the protective layer 2 and sprayers 5. Fabric 1 withthe silicone, polyurethane or acrylic emulsion 4 is pressed throughlaminating rollers at a pressure exerted by the rollers comprisedbetween 1 and 100 bar to penetrate the silicone, polyurethane or acrylicemulsion 4 into fabric 1 and remove the exceeding quantity.

In a subsequent step of the process the silicone, polyurethane oracrylic emulsion 4 in fabric 1 is dried, in particular through a heattreatment in an oven at a temperature comprised between 20° and 200° C.,for a time comprised between 2 and 40 hours. At the end of this dryingstep fabric 1 is impregnated with a percentage of silicone, polyurethaneor acrylic emulsion 4 comprised between 1% and 60% of the weight offabric 1.

Referring to FIG. 3, it is seen that in a subsequent optional step ofthe process, an aliphatic solution 6 is sprayed by means of the samesprayers 5 or of other sprayers onto fabric 1, so as to apply a basisweight of the aliphatic solution 6 comprised between 48 and 90 g/m², inparticular 55 g/m²±10% or 80 g/m²±10%, after which the aliphaticsolution 6 is dried.

The aliphatic solution 6 comprises polyacrylates, glycols and/oraliphatic polyurethane compounds, in particular opacifiers. Thealiphatic solution 6 can also comprise silicon-oxygen chains.

Referring to FIG. 4, it is seen that in a further optional step of theprocess, an aqueous emulsion 7 of isocyanate and/or crosslinkingpolyurea substances is sprayed by means of the same spraying 5 or ofother sprayers onto fabric 1, after which this aqueous emulsion 7 isdried.

The basis weight of the fabric 1 at the end of the process is preferablycomprised between 260 and 320 g/m².

In an alternative embodiment, the silicone, polyurethane or acrylicemulsion 4 can be applied to fabric 1 in the described above mannerbefore applying the protective layer 2.

In a final operating step, at least one edge of fabric 1 impregnatedwith the silicone, polyurethane or acrylic emulsion 4 and joined to theprotective layer 2, if any, is folded and sewn on itself so as to form ahem.

Possible variants and/or additions may be made by those skilled in theart to the embodiment of the invention here described and illustratedremaining within the scope of the following claims. In particular,further embodiments of the invention may include the technical featuresof one of the following claims, with the addition of one or moretechnical features, taken individually or in any mutual combination,described in the text and/or illustrated in the drawings.

The invention claimed is:
 1. Process for manufacturing carbon fiberfabrics, said process comprising: providing a carbon fiber fabric, thecarbon fiber fabric having at least one protective layer applied ontoone side, the protective layer including a film, a woven fabric or anonwoven fabric; impregnating the carbon fiber fabric with a silicone,polyurethane or acrylic emulsion; and drying the impregnated carbonfiber fabric to provide a dried carbon fiber fabric with a flexibilitysufficient to allow deformation along two transversal axes of curvaturewherein the dried carbon fiber fabric is foldable; wherein an aliphaticsolution is sprayed on the fabric and thereafter dried; and wherein thealiphatic solution comprises polyacrylates or glycols.
 2. Processaccording to claim 1, wherein the silicone, polyurethane or acrylicemulsion is applied to the fabric by means of spraying, smearing,immersion or with a “hot-melt” transfer procedure.
 3. Process accordingto claim 1, wherein the fabric is impregnated with a percentage ofsilicone, polyurethane or acrylic emulsion between 1% and 60% of theweight of the fabric.
 4. Process according to claim 1, wherein beforedrying the fabric with the silicone, polyurethane or acrylic emulsion ispressed at a pressure between 1 and 100 bar.
 5. Process according toclaim 1, wherein the protective layer is applied by means of alamination to the side of the fabric.
 6. Process according to claim 5,wherein said lamination is carried out at a temperature between 30° C.and 200° C. and/or at a pressure between 10 and 200 bar.
 7. Processaccording to claim 1, wherein the silicone, polyurethane or acrylicemulsion is applied to the fabric before the protective layer is appliedto the fabric.
 8. Process according to claim 1, wherein the protectivelayer comprises a polyurethane, polyamide or acrylic film.
 9. Processaccording to claim 1, wherein the protective layer is applied to thefabric by means of a lamination, in particular a hot calendering orpressing, in which the surface of the protective layer contacting thefabric partially penetrates the fabric, so as to create an intermediatelayer in which the outer filaments of the fabric are integral with theprotective layer.
 10. Process according to claim 9, wherein thethickness of the intermediate layer is between 5% and 60% of thethickness of the fabric.
 11. Process according to claim 1, wherein thebasis weight of the aliphatic solution is between 48 and 90 g/m². 12.Process according to claim 1, wherein the aliphatic solution furthercomprises aliphatic polyurethane compounds.
 13. Process according toclaim 1, wherein the aliphatic solution further comprises silicon-oxygenchains.
 14. Process according to claim 1, wherein an aqueous emulsion ofisocyanate and/or crosslinking polyurea substances is sprayed on thefabric dried.
 15. Process according to claim 1, wherein the basis weightof the fabric at the end of the process is between 260 and 320 g/m². 16.Process according to claim 1, wherein at least one edge of the fabricimpregnated with the silicone, polyurethane or acrylic emulsion andjoined to the protective layer is folded and sewn on itself so as toform a hem.
 17. Process according to claim 1, wherein the basis weightof the aliphatic solution is 55 g/m²±10%.
 18. Process according to claim1, wherein the basis weight of the aliphatic solution is 80 g/m²±10%.